Clinicopathological factors associated with BRAF-V600E mutation in colorectal serrated adenomas

Serrated adenomas are genetically heterogeneous, and the histological classification into sessile serrated (SSA) adenoma and traditional serrated adenoma (TSA) does not reflect the molecular landscape. The objective of this study was to assess clinical or pathological factors associated with BRAF-V600E mutation in serrated adenomas. Systematic review and meta-analysis was performed by searching electronic databases from January 2011 to January 2019 for studies assessing the association of BRAF-V600E mutation with clinical or pathological features of serrated adenomas. Odds ratio (OR) was calculated for each factor; a P-value <0.05 was considered significant. Forty studies assessing 3511 serrated adenomas (2375 SSAs and 1136 TSAs) were included. BRAF-V600E mutation was significantly associated with proximal localisation (OR = 2.71; P < 0.00001) and CIMP-H status (OR = 4.81; P < 0.0001) in both SSA and TSA, with polyp size <10 mm (OR = 0.41; P = 0.02) in TSA, and with endoscopic pit pattern II-O (OR = 13.11; P < 0.00001) and expression of MUC5A5 (OR = 4.43; P = 0.003) and MUC6 (OR = 2.28; P < 0.05) in SSA. Conversely, BRAF mutation was not associated with age <70 years (OR = 1.63; P = 0.34), age <60 years (OR = 0.86; P = 0.79), female sex (OR = 0.77; P = 0.12), flat morphology (OR = 1.52; P = 0.16), presence of any dysplasia (OR = 1.01; P = 0.59), serrated dysplasia (OR = 1.23; P = 0.72) and invasive cancer (OR = 0.67; P = 0.32), nuclear β-catenin expression (OR = 0.73; P = 0.21) and p53 overexpression (OR = 1.24; P = 0.82). In conclusion, BRAF-V600E mutation is associated with proximal localisation and CIMP-H status in both SSA and TSA, with size <10 mm only in TSA, and with expression of MUC5A5 and MUC6 and endoscopic pit pattern II-O at least in SSA. In serrated adenomas, BRAF-V600E mutation does not seem to be associated with age and sex, with the prevalence of dysplasia and cancer and with the morphology of the dysplastic component.

Loss of PTEN expression as diagnostic marker of endometrial precancer: A systematic review and meta-analysis

INTRODUCTION

Endometrial hyperplasia may be either a benign proliferation or a premalignant lesion. In order to differentiate these two conditions, two possible histologic classifications can be used: the World Health Organization (WHO) classification and the endometrial intraepithelial neoplasia (EIN) classification. The 2017 European Society of Gynaecological Oncology guidelines recommend the use of immunohistochemistry for tumor suppressor protein phosphatase and tensin homolog (PTEN) to improve the differential diagnosis. Nonetheless, its diagnostic accuracy has never been defined. We aimed to assess the diagnostic accuracy of immunohistochemistry for PTEN in the differential diagnosis between benign and premalignant endometrial hyperplasia.

MATERIAL AND METHODS

Electronic databases were searched from their inception to May 2018 for studies assessing immunohistochemical expression of PTEN in endometrial hyperplasia specimens. PTEN status ("loss" or "presence") was the index test; histological diagnosis ("precancer" or "benign") was the reference standard. Sensitivity, specificity, positive and negative likelihood ratios (LR+, LR-), diagnostic odds ratio (DOR), and area under the curve (AUC) on summary receiver operating characteristic curves were calculated (95% CI), with a subgroup analysis based on the histologic classification adopted (WHO vs EIN).

RESULTS

Twenty-seven observational studies with 1736 cases of endometrial hyperplasia were included. Pooled estimates showed low diagnostic accuracy: sensitivity 54% (95% CI 50%-59%), specificity 66% (63%-69%), LR+ 1.55 (1.29-1.87), LR- 0.72 (0.62-0.83), DOR 3.56 (2.02-6.28), AUC 0.657. When the WHO subgroup was compared with the EIN subgroup, higher accuracy (AUC 0.694 vs. 0.621), and higher heterogeneity in all analyses, were observed.

CONCLUSIONS

Immunohistochemistry for PTEN showed low diagnostic usefulness in the differential diagnosis between benign and premalignant endometrial hyperplasia. In the absence of further evidence, the recommendation about its use should be reconsidered.